IgE binding to peanut allergens is inhibited by combined d-aspartic and d-glutamic acids

Role of D-aspartate on biosynthesis, racemization, and potential functions: A mini-review

D-aspartate, a natural and endogenous amino acid, widely exists in animal tissues and can be synthesized through aspartate racemase and transformed by D-aspartate oxidase (DDO). D-aspartate mainly serves as a neurotransmitter and has been demonstrated to exhibit various physiological functions, including nutritional potential, regulation on reproduction and hormone biology, and neuron protection. This article mainly reviews the synthesis, racemization, and physiological functions of D-aspartate with emphasis on the potential in diseases.

Simple methods to reduce major allergens Ara h 1 and Ana o 1/2 in peanut and cashew extracts

Whole peanut or cashew extracts are usually used in immunotherapy. Reducing major allergen(s) in the extracts may lessen their side effects. Three methods were evaluated to reduce major allergens in peanut extracts: (1) p-aminobenzamidine; (2) magnetic agarose beads; and (3) extraction of a commercial peanut flour at pH 7, respectively. The first two methods were also used to reduce major allergens in cashew extracts. After treatments, samples were evaluated by SDS-PAGE. pABA-treated samples were also analyzed for IgE binding in western blot. We found that the methods resulted in peanut extracts lacking detectable Ara h 1 but containing Ara h 2/6 and cashew extract lacking Ana o 1/2, but containing Ana o 3. Consequently, reduced IgE binding was observed. We conclude that the methods are useful for producing peanut or cashew extract with little Ara h 1 or Ana o 1/2.

Treatment with oleic acid reduces IgE binding to peanut and cashew allergens

Oleic acid (OA) is known to bind and change the bioactivities of proteins, such as α-lactalbumin and β-lactoglobulin in vitro. The objective of this study was to determine if OA binds to allergens from a peanut extract or cashew allergen and changes their allergenic properties. Peanut extract or cashew allergen (Ana o 2) was treated with or without 5mM sodium oleate at 70°C for 60 min (T1) or under the same conditions with an additional overnight incubation at 37°C (T2). After treatment, the samples were dialyzed and analyzed by SDS-PAGE and for OA content. IgE binding was evaluated by ELISA and western blot, using a pooled serum or plasma from individuals with peanut or cashew allergies. Results showed that OA at a concentration of 5mM reduced IgE binding to the allergens. Peanut sample T2 exhibited a lower IgE binding and a higher OA content (protein-bound) than T1. Cashew allergen T2 also showed a reduction in IgE binding. We conclude that OA reduces the allergenic properties of peanut extract and cashew allergen by binding to the allergens. Our findings indicate that OA in the form of sodium oleate may be potentially useful as a coating to reduce the allergenic properties of peanut and cashew allergens.